NIH sponsored cancer researchers have been obtaining promising results using molecules radiolabeled with lead-212 in treatment for metastatic melanoma and disseminated colon and pancreatic cancers. Another isotope, radium-223 is being used in clinical trials in treatment of skeletal metastases. There is no effective therapy for these diseases. Together 199,280 people in the US will be diagnosed this year and 97,070 will die from these diseases (American Cancer Society 2005 Cancer Facts and Figures). This promising cancer research must be supported with additional quantities of the isotope if this research is to proceed to later stage clinical trials and approved drug products. Also, additional amounts of the isotopes are required to support increased research on other cancers that will be undertaken as papers are published discussing the therapeutic effect achieved in current research. This grant application will increase the amount of these isotopes by processing and purifying actinium-227, an isotope used in the production of neutron generators produced years ago and are now being disposed of. Two sources have been obtained, totaling 1.5 Ci. Actinium-227 once purified can be processed for Ra-223. It can also be irradiated to produce thorium-228, a precursor isotope to Pb-212. As a result of implementing this Phase I grant application, Ac-227 will be separated from these sources and separation techniques yielding high quality Ra-223 will be demonstrated. Additional sources of Ac-227 will be identified and candidate reactors for Ac-227 irradiations required for the production of Th-228 will be identified. As a result of implementing a Phase II grant, curie quantities of Ra-223 and Th-228/Pb-212 will be available at purity levels required for medical research. -Relevance This Phase I grant application and a follow-on Phase II application proposes to increase the amount of radioisotopes required to support later stage research and anticipated approved drug products in therapies that are showing promise in cancer therapies. NIH funded researchers have been obtaining promising results using molecules radiolabeled with lead-212 in treatment for metastatic melanoma and disseminated colon and pancreatic cancers. Another isotope, radium-223 is being used in clinical trials in treatment of skeletal metastases. [unreadable] [unreadable] [unreadable]